The latest version of Griffin's TuneJuice battery pack is here in the form of TuneJuice Universal ($25), a clean little soft touch black and chrome plastic enclosure that includes the first set of three AA batteries you can use to replenish a depleted iPod or iPhone -- assuming that you supply your own USB cable. Griffin claims that TuneJuice Universal adds 2.25 hours of talk time to the iPhone 3GS, which is to say a little under half its original run time or roughly 700mAh of power from the AAs. TuneJuice Universal turns itself on and off automatically when a device is connected, requiring no buttons or switches of its own, and has a yellow power light to indicate that it's on.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.